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DIY Turbo Discussion greddy on a 1.8? homebrew kit?

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Old 05-20-2012, 12:30 AM   #1
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Default Boost problem

So, I'm having one hell of a boost problem, and I'm hoping one of you yahoos can help me figure out what it is.

Yesterday, I installed a MBC and started tuning the car. Accidentally took it to 210ish kpa. But ever since then, I've been unable to build boost.

Ever since then, I haven't been able to get it above 130kpa. Today, I tightened the ---- out of all of my t-bolt clamps, and it managed to make it to a peak of almost 140ish kpa. I'm pretty confident the boost leak is not from any of my couplers at this point.

I'll be building a DIY boost leak tester tomorrow, and picking up some hairspray too, but I'm looking for any other avenues I could check and/or potentially find a way to hunt down the problem and fix it tonight.
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Old 05-20-2012, 12:50 AM   #2
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wga operating correctly?
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Old 05-20-2012, 01:00 AM   #3
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Quote:
Originally Posted by 18psi View Post
wga operating correctly?
....Embarassingly, I completely forgot to check this. Going out to check it right now, thank you 18psi.
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Old 05-20-2012, 01:07 AM   #4
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Pulling off the actuator, the wastegate flapper moves easily. The actuator holds it shut tightly.

I'm not even gonna try to force that actuator open this late, but I don't think the wastegate is necessarily a concern due to that - I mean, if it was wastegate related, it would overboost right?
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Old 05-20-2012, 02:24 AM   #5
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Blown out gaskets? what kind of MBC?
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Old 05-20-2012, 02:31 AM   #6
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Brand new exhaust manifold gasket (< 100 miles), no turbo gaskets with brand new surfaces, fleabay ball and spring MBC. I can remove the MBC if needed no problem to test.
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Old 05-20-2012, 08:24 PM   #7
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overtightened t-bolt clamp sliced a silicon hose somewhere?
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Old 05-20-2012, 08:42 PM   #8
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instead of just moving the flapper i would suggest hooking it up to a pressured air source/gauge and verifying that actually moves at whatever your wg spring pressure is..
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Old 05-20-2012, 11:25 PM   #9
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Answer, for future searching:

I am using an eBay BOV. When I took it to 16.5psi, it somehow bent the internal shaft in the BOV, and it no longer operates correctly.

That's where the problems stem from. The BOV is acting as a giant boost leak.

Now, time to start a BOV thread.
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Old 05-20-2012, 11:30 PM   #10
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get non-knockoff valve
profit
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Old 05-20-2012, 11:37 PM   #11
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What's the cheapest non-knockoff valve available atm 18psi?
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Old 05-21-2012, 12:08 AM   #12
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a used one
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Old 05-21-2012, 12:19 AM   #13
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Old 05-21-2012, 12:31 AM   #14
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Checked that, I'm not Socal Cpolly.
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Old 05-21-2012, 01:24 AM   #15
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depending what flange your using, cheapest to use would be dsm let off valve from a 1g talon
can pick them up for 10-30 bucks, good for 20-25psi, and make a pretty loud whoosh when releasing. just note, it will open in vacuum
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Old 05-21-2012, 01:58 AM   #16
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x2 for a DSM bov. Hit a junkyard and it'll be $10. Definitely a little noisy in vac if it's vented (vibrating/wheeze sound) but stock holds great to about 15psi, with the "Dodge Garage" mod good for 25+. I've got one on my Miata. Can also be made to fit a Greddy flange if you drill a couple extra holes in it.
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Old 05-21-2012, 02:33 AM   #17
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1g DSM BOV purchased and hopefully will be in the mail tomorrow.

Just dropped a ton of props for being generally awesome.
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